Amnesty International has found:
Fresh evidence ... that members of the armed group calling itself the Islamic State (IS) have launched a systematic campaign of ethnic cleansing in northern Iraq, carrying out war crimes, including mass summary killings and abductions, against ethnic and religious minorities.
The phrase is repellant but accurate.
And if you know about it, then the question becomes, what can be done to stop it? And, if something can be done, should it?
And will it?